Photovoltaic (PV) cells, also commonly referred to as solar cells, convert the energy from sunlight directly into electricity by the photovoltaic effect. Until recently, most PV cells were formed of semiconductor-grade crystalline-silicon wafers, which are expensive to produce. Now, less labor-intensive and easier to manufacture thin-film PV cells, which are made by depositing one or more thin layers of photovoltaic material on a substrate, are becoming more common.
When more electricity is required than a single PV cell can deliver, multiple PV cells can be electrically connected together and packaged to form a PV module or panel. Multiple PV modules may then be arranged to form a PV solar array.
To form a PV module, the individual PV cells must be electrically interconnected. This has been traditionally accomplished by connecting the PV cells with conductive ribbons or wires in an under-and-over stringing and welding of the cells. These connection methods are costly and time-consuming and are part of the reason why PV modules are still too labor-intensive for many applications.